The present disclosure provides a method for forming a semiconductor structure. The method includes the following operations. A metal layer is formed. An adhesion-enhancing layer is formed over the metal layer. A dielectric stack is formed over the adhesion-enhancing layer. A trench is formed in the dielectric stack. A barrier layer is formed conforming to the sidewall of the trench. A high-k dielectric layer is formed conforming to the barrier layer. A sacrificial layer is formed conforming to the high-k dielectric layer.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The method of claim 1, wherein the sacrificial layer is removed by a hydrofluoric vapor (HF) etching operation.
4. The method of claim 1, wherein forming the dielectric stack comprises forming a silicon-rich silicon nitride interfacing with the adhesion-enhancing layer.
6. The method of claim 1, wherein a top surface of the contact is higher than a top surface of the high-k dielectric layer.
9. The method of claim 7, wherein the adhesion-enhancing layer is formed by introducing silane to the metal layer.
10. The method of claim 7, wherein the silicon-rich silicon nitride layer contacts the adhesion-enhancing layer.
12. The method of claim 11, wherein the barrier layer surrounds the contact and laterally spaces the contact and the dielectric stack.
13. The method of claim 11, wherein a portion of the barrier layer is above the dielectric stack.
16. The method of claim 14, wherein a top surface of the contact is higher than a top surface of the dielectric stack.
17. The method of claim 14, wherein the dielectric stack is separated from the conductive pad.
18. The method of claim 14, wherein a first portion of the contact proximal to the metal layer has a first width narrower than a second width of a second portion of the contact distal to the metal layer.
19. The method of claim 1, wherein a cross sectional profile of the adhesion-enhancing layer comprises a thicker center and a thinner edge.
20. The method of claim 1, wherein forming the adhesion-enhancing layer comprises introducing silane to react with the metal line.
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July 29, 2022
September 10, 2024
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